Pneumatic hydraulically controlled door operating mechanism



NOV. 18, 1952 SEAGREN 2,618,365

PNEUMATIC HYDRAULICALLY CONTROLLED DOOR OPERATING MECHANISM Filed July26, 1948 2 SHEETSSHEET 1 :E .L. INVENTOR. 7 N 5 15's agrerz ATTORNEYNOV. 18, 1952 N G SEAGREN 2,618,365

PNEUMATIC HYDRAULICALLY CONTROLLED DOOR OPERATING MECHANISM Filed July26, 1948 2 SI-EETS-Sl-IEE'I 2 U Jim;

33 I T 7 5" r .4 4. I i INVENTOR.

\ I BY s ggrerz,

ATTORNEX Patented Nov. 18, 1952 PNEUMATIC HYDRAULICALLY CONTROLLED DOOROPERATING MECHANISM Nils G. Seagren, South Pasadena, Calif., assignor,by mesne assignment-s, to Astra Engineering Company, a corporation ofCalifornia Application July 26, 1948, Serial No. 40,706

4 Claims.

This invention relates to a device for pneumatically opening and closingdoors together with hydraulic means for controlling the pneumaticoperation of such doors.

While doors'generally are manually operated, there are many places andnumerous instances where such manual operation is both inconvenient. andcumbersome. This is particularly the case in establishments such ashospitals and wherever wheel chairs, floor trucks, push carts andsimilar vehicles are to be moved through doorways which are fitted withnormally closed doors, or where large trays and other bulky loads are tobe carried through such doors.

It is the general object of the invention to provide a simple,inexpensive and conveniently operable device so designed, constructedand arranged that the operator of the vehicle pr the person carryingsuch load may actuate the mechanism of the invention to move the doorwithout delaying, interrupting or otherwise interferring with theoperation of the vehicle or transportation of such load. A furtherobject of the invention is to provide a door opening mechanism whichwill instantly commence to swing the door into open position and, as itapproaches fully open position, will check the movement thereof so as tobring the door gently into fully open position.

Another object is the provision of means for momentarily delayingclosing movement of the door and for initiating such closing movementslowly thereby to offer the operator time to move the vehicle throughand completely away from the closing door. A still further object is toprovide. means for checking the final closing movement of the door,thereby to bring the door into closed position without bang or jar.

These and other objects of th invention, as well as the. manyadvantageous. features thereof, will be better understood from thefollowing detailed description and by referring to the drawings, inwhich a preferred form of the invention is illustrated.

In the drawings:

Fig. l is a front elevational view of a door operating mechanismembodying the invention;

Fig. 2 is a substantially corresponding plan view of the device;

Fig. 3 is a side view, on a larger scale, of the pneumatic and hydrauliccylinder combination of the device;

Figs. 4 and 5 are detai1 views, on a still larger scale, of certainimportant elements of the cylinder combination; and

Fig. 6' shows a needle valve of the device, the function of which willbe hereinafter fully described.

As indicated in the drawings, a door A is hung in a conventional framingB on hinges C and it is shown fitted with a bracket I at the top thereofin position pivotally to support the piston rod 2 of a cylindercombination. The latter terminates in a lug 3 which is pivotally hung ina bracket 4 of the wall B.

The cylinder combination is, as best indicated in Fig. 3, composed oftwo parts, namely a pneumatically actuated operating section 5 and ahydraulic movement-control mechanism 6. The section 5 includes acylinder 1, the inner end of which is shown threaded to receive thereina screwplug 8, from which the aforenamed lug- 3 extends. A piston 9 issecured to the inner end of the piston rod 2 and it is by a spring [0urged in the door closing direction indicated by the arrow II.

In a. cabinet [5 is mounted a pressure regulator I6 which, through aconduit I1, is in communication with a source of air under pressure.Since such source of compressed air is commonly found in establishmentswhere the device of my invention is mostly used and because any suitableconventional air compressor may be employed, such is not illustrated inthe drawings. Adjacent the pressure regulator I6 is mounted a valve l8,from one port of which leads a conduit 19 to the regulator l6, and aflexible conduit 20 extends from the valve to the inner end of thecylinder 1, through the screw plug 8. This valve is electricallyoperated and the operating mechanism is actuated by a person pushing avehicle, carrying a load, or just walking toward the door. in anysuitable manner.

Illustrative of a preferred form of electrical valve operatingmechanism, I have, in Fig. 2, diagrammatically shown a pad 2i placed onthe floor and extending such a distance from-both sides of the dooropening as may be found most convenient for the purposes of theinvention. Between this pad and the floor surface are placed contactmembers consisting of thin sheets 22, 2-3 of current conducting materialforming the terminals of an electric circuit. Between these sheets andsecured thereto are a number of equidistantly spaced discs 24 ofinsulating material, merely thick enough to maintain the sheetssufficiently spaced apart to maintain the circuit open. When soconstructed, it is found that; pressure against the pad by the vehicleor the foot of the operator will bring the sheets into 3 contact witheach other at some point or points between the discs thereby to closethe circuit through a source of energy 23. A magnet 21 in the circuit isthereby energized to open a passage through the valve and the conduitfor the pressure fluid to the cylinder 1, to cause the piston 9 toadvance, against the tension of the spring l0, and quickly to move thedoor toward fully open position. The space between the sheets 22, 23, atthe outer edges thereof, is tightly closed by a strip 25 which also ismade from insulating material.

It was above stated that one of the objects of the invention is toprovide means for checking the movement of the door as it approachesfully open position. The piston rod 2 is, for this purpose, made with anenlargement 33 which, as the piston advances to open the door, entersinto a recess 34 of a screw plug 35 which closes the end of the cylinder6 and serves as a guide for the piston rod. This recess is slightlylarger in diameter than the enlargement 33 of the piston rod. Thecylinder 6 is filled with a liquid such as used in shock absorbers andwhen so filled it is found that the enlargement 33, upon entering therecess 34, is forced to expel the fluid from within the recess and in"so doing to check the movement of the piston rod as the door moves intofully open position.

The cylinders 5 and 6 are fastened together i by means of a connectingmember 31, the ends of which are threaded to engage screw threads of thetwo cylinders, substantially as indicated in Fig. 3. It is noted thatthe end of this member which extends into the cylinder 6 is providedwith a recess 38 of a size freely to receive an enlargement 39 of thepiston rod for the purpose which will be explained presently. Inaddition, it is important to note that a conduit 43 interconnects theends of the cylinder 6 at points directly in front of the recesses 34and 3B. The piston rod is, between the enlargement 33 and 39, made witha piston 36 which is freely fitted within the cylinder and, as thepiston rod moves to open the door, advances Within the cylinder therebygently to force the fluid therein through the conduit 40 to the rear endof the piston, a portion of the fluid being free to flow through thenarrow annular space between the piston and the cylinder.

In order more completely to control the speed of opening movement of thedoor I have, in Fig. 4 shown the central control member of the pistonrod made in two parts which are secured in position on the piston rod bymeans of pins or set screws 45, 46. A washer 42 is placed on the rodbetween these two parts and it is by a resilient gasket 43, of thecommercially well known 0 type, held in contact with the rear endsurface of the piston 36. A number of fine passages 44 are cut throughthe piston, but these passages are normally held closed by the washer42. When the valve is thrown to initiate advance movement of the piston36, it is found that the fluid in front of the advancing piston flowingthrough the passages 44 exerts sufficient pressure against the washer 42to cause the latter to recede and so to uncover these passagessufficiently to relieve the pressure in front of the piston. The initialopening movement of the door will, for this reason and because the fluidalso flows through the conduit 40 and past the piston, not be delayed.This movement continues until the enlargement 33 reaches the recess 34whereupon, as above stated, further advancement is checked to bring thdoor to a sto gently. In other words, this combination constitutes adash-pot controlling the final opening movement of the door.

In order better to control the speed of movement of the door, it ispreferred to provide aneedle valve 4| in the conduit 40 for manualoperation to adjust the opening of the passage through this conduit. Thedoor will remain open until the vehicle, or the person passing throughthe door opening, or both, have cleared the pad 21, whereupon thecircuit automatically opens to permit the valve 18 to return to itsinitial position and so to relieve the pressure within the cylinder 5.The spring I0 is now free to return the piston rod on the door toclosing position, but this movement is delayed until the enlargement 33leaves the recess 34, so that the initial closing movement of the dooris effected slowly until the enlargement passes out of this recess. Theclosing movement continues at increased speed until the piston rodenlargement 39 enters the recess 33, similarly to check the finalclosing movement of the door. This completes the cycle of operation.

Since the enlargement 39 remains seated within the recess 38, it isfound that subsequent opening movement would be initiated slowly, untilthe enlargement has passed out of the recess. Such delay isobjectionable and provision is, for this reason, made for expediting theinitial opening movement. Such means may tak the form of a check valve3|] which is placed within the enlargement 34, substantially asindicated in Fig. 4.

It was above stated that the spring ll) quickly returns the door toclosed position. I have found it advantageous, however, to providepneumatic means for effecting the door closing movement. Illustrative ofsuch means I have shown a second pressure regulator 50 placed within thecabinet I5. Air from the conduit l1 passes through this regulator and aconduit 52 to the other end of the pneumatic cylinder 1. This secondregulator should be properly adjusted to effect the closing movement ofthe door at the required rate of speed. It is also important to notethat, because this pressure is continuously maintained, the regulator Itmust be adjusted to provide sufficient pressure not only to overcome thepressure tending to close the door but also to open the door at therequired speed. Where such pneumatic door closing arrangement isprovided, the spring HJ may be omitted. A relief valve 53 is incommunication with the conduit 52 and this valve should be set for aslightly higher pressure than registered by the regulator 50 in order toprevent waste of the pressure fluid but so that the fluid ahead of thepiston 9 may discharge through this gelief valve during the openingmovement of the cor.

In places where swinging doors are installed, it is sometimes found thata draft is present on the premises of sufiicient force to swing the dooropen and to maintain it partly open. When the pneumatic door closingarrangement of my invention is applied to a door in such places, it isfound that it can be adjusted to maintain the door normally closed.

It is, of course, necessary to provide within the piston rod bearingpackin designed to prevent leakage of the fluids within the cylinders,but as such are commonly used in devices of the type herein considered,it is not believed necessary to burden the drawings with illustrationsthereof. Even when such packing is provided, it may be found that aslight leakage of fluid from the front end of the cylinder may occurandthat if such leakage should occur, the result would be that the leakingfluid woulddrop from the end of the cylinder to the floor. It may, forthis reason, he found advisable to fit a cap 60 over the threaded end ofthe plug 35, within which such slight amount of fluid as may leakthrough this plug would be free to accumulate. The cap is made with apassage 6| which, when the cap is screwed tightly in place, will take a.position at the top of the cap, as shown. The cap may from time to timebe loosened to bring this passage to the bottom thereof and so to permitany slight accumulation of fluid to discharge therefrom.

The device of the invention, as above described, does not interfere withmanual operation of the door which will continue to function in theconventional manner in case the operating mechanism should becomeineffective, as by interruption of the electric circuit. But while Ihave in the foregoing described a preferred form of the invention, I donot wish to be limited to the exact sizes, proportions and arrangementsshown, but reserve the right to embody therein modifications within thescope of the claims hereto appended.

I claim:

1. In a door operating mechanism, means for controlling the operation ofthe door comprising, a cylinder, a door check fluid within saidcylinder, a closure for each end of the cylinder, each closure having inthe inner surface thereof a cylindrical recess communicating with thespace within the cylinder, a cylindrical member within the cylinderincluding a, central piston portion slidable within the cylinder, a headat each end thereof and reduced portions intermediate said heads and thecentral piston thereof, the heads being slightly smaller in diameterthan the recesses of the closures, there being a passage through one ofsaid heads, a check valve in said passage, and a by-pass conduitinterconnecting the ends of the space within the cylinder.

2. In a door operating mechanism, means for controlling the operation ofthe door comprising, a cylinder, a door check fluid within saidcylinder, a closure for each end of the cylinder, each closure having inthe inner surface thereof a cylindrical recess communicating with thespace within the cylinder, a cylindrical member within the cylinderincluding a central piston portion slidable within the cylinder, 9, headat each end thereof and reduced portions intermediate said heads and thecentral piston thereof, the heads being slightly smaller in diameterthan the recesses of the closures, there being a passage through one ofsaid heads, a check valve in said passage, a by-pass conduitinterconnecting the ends of the space within the cylinder, and a valvecontrolling the passage through said conduit.

3 In a door operating mechanism, means for controlling the operation ofthe door comprising,

a cylinder, a door check fluid within said cylinder, a closure for eachend of the cylinder, each closure having in the inner surface thereof acylindrical recess communicating with the space within the cylinder, acylindrical assembly comprising a shaft, two members fastened end to endon the shaft, one member having an enlarged portion thereon adjacent theother member and forming a piston freely slidable within the cylinder,said piston having passages therethrough, an annular plate on the othermember, means urging said plate against the piston to close saidpassages, the members having heads at the ends thereof for passage intosaid recesses to check sliding movement of the assembly within thecylinder, and a by-pass conduit interconnecting the ends of the spacewithin the cylinder.

4. In a door operating mechanism, means for controlling the operation ofthe door comprising, a cylinder, a door check fluid within saidcylinder, a closure for each end of the cylinder, each closure having inthe inner surface thereof a cylindrical recess communicating with thespace within the cylinder, a cylindrical assembly comprising a shaft,two members fastened end to end on the shaft, said members having headsat the outer ends thereof for passage into said recesses to checksliding movement of the assembly within the cylinder, one member havingan enlarged portion thereon adjacent the other member and forming apiston freely slidable within the cylinder, said piston having passagestherethrough, the inner end of the other member being reduced indiameter to form a recess adjacent the piston, a washer in said recess,a resilient element in the recess urging the washer against the pistonto close said passages, and a by-pass conduit interconnecting the endsof the space within the cylinder.

NILS G. SEAGREN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 522,508 Canet July 3, 1894606,640 Bennik July 5, 1898 612,324 Frazier et al. Oct. 11, 18981,037,267 Knight Sept. 3, 1912 1,338,906 Coulson May 4, 1920 1,540,972Weeks June 9, 1925 1,722,920 7 Hynes July 30, 1929 1,737,433 RowntreeNov. 26, 1929 1,859,364 Haskell May 24, 1932 1,950,685 McGee Mar. 13,1934 2,151,851 Briggs Mar. 28, 1939 2,395,027 Whisler Feb. 19, 1946FOREIGN PATENTS Number Country Date 311,392 Italy Sept. 29, 1933

